Drivers Side Axle Failure on Track

[ddozier]

I was at Road Atlanta last weekend and on Saturday 2nd session and on the 2nd lap I had the drivers side axle shaft fail as I got back on the power through turn 6. The car lost all drive and as you can hear in the video made a horrible sound.

They pulled me back to the pits and I started to work on the removal of the shaft, I was able to get it out quickly and after calling the local Ford dealer we were able to find a replacement within 30 miles of the track. I ran and got the new parts and had the car back out for the afternoon sessions. The new unit has held up fine for the remainder of the weekend. The original axle had 6 track days and about 7500 miles on it.

The shaft that failed had the inner CV joint fail. It appears the inner joints retaining ring had either popped out of the grove or was never properly seated into the grove. The cage portion of the joint was then free to move outside the cup that it is supposed to stay in. Once the cage moved out enough to allow the cage to not retain one of the 8 ball bearings the joint failed. Everything stayed inside the boot and all the pieces were present when I disassembled the joint. The retaining ring was wound up into a ball and in the boot. My guess is the ring was only partially seated in the grove and with the riggers of track duty it popped out of place or was pulled out by the cage, not really sure.

I am hoping the failure was a fluke and not a sign of things to come. I will likely carry a spare axle shaft for both sides as they are cheap and easy to install at the track if it becomes and issue.

I just wanted to document this here in case there are other failures maybe we can see a pattern.

Video of the failure is here:
[ame]

Dave

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[Plimmer]

Thanks for sharing. My 2015 broke 3 of the 4 boots at my first track day, leaving a big greasy mess under my car.

I tossed them out and installed DSS800 axles instead. So far they have been running perfectly.

 

[ihavefat]

I was at Road Atlanta last weekend and on Saturday 2nd session and on the 2nd lap I had the drivers side axle shaft fail as I got back on the power through turn 6. The car lost all drive and as you can hear in the video made a horrible sound.

They pulled me back to the pits and I started to work on the removal of the shaft, I was able to get it out quickly and after calling the local Ford dealer we were able to find a replacement within 30 miles of the track. I ran and got the new parts and had the car back out for the afternoon sessions. The new unit has held up fine for the remainder of the weekend. The original axle had 6 track days and about 7500 miles on it.

The shaft that failed had the inner CV joint fail. It appears the inner joints retaining ring had either popped out of the grove or was never properly seated into the grove. The cage portion of the joint was then free to move outside the cup that it is supposed to stay in. Once the cage moved out enough to allow the cage to not retain one of the 8 ball bearings the joint failed. Everything stayed inside the boot and all the pieces were present when I disassembled the joint. The retaining ring was wound up into a ball and in the boot. My guess is the ring was only partially seated in the grove and with the riggers of track duty it popped out of place or was pulled out by the cage, not really sure.

I am hoping the failure was a fluke and not a sign of things to come. I will likely carry a spare axle shaft for both sides as they are cheap and easy to install at the track if it becomes and issue.

I just wanted to document this here in case there are other failures maybe we can see a pattern.

Video of the failure is here:


Dave

I wonder maybe if this is 2015 issue or would 2016+ may possibly have that issue as well at the track? If that's the case I may need to purchase extra ones to carry around for track days Lol

 

[DAVECS1]

I have a 2017 GT PP that also failed the Driver's side half shaft. I had 1478 miles on the car. My only modifications are delrin cradle bushings and billet verticle links. I was playing with the launch control, when mine failed. Looking back, It had become more noisy after my track day at Autobahn in Joliet, IL. I replaced mine with the GT350 halfshafts as they can be had for a decent price.

 

[Tommy V]

I have a set of stock ones i could sell,I have a 2015 gt/pp that i changed the axles out on,they only 2300 miles on them.Pm me if u are interested.

 

[ddozier]

I have a 2017 GT PP that also failed the Driver's side half shaft. I had 1478 miles on the car. My only modifications are delrin cradle bushings and billet verticle links. I was playing with the launch control, when mine failed. Looking back, It had become more noisy after my track day at Autobahn in Joliet, IL. I replaced mine with the GT350 halfshafts as they can be had for a decent price.

My CV cup housing looked just like yours when I took it apart.

I am curious about the GT350 shafts, does the two CV joints look to be any different. On Ford Performance they describe the shaft diameter to be larger but nothing about the CVs them selves.

Levittown has the GT350 shafts for $320.00 for both shafts. If they are a different CV design I will buy them and pull the GT shafts and store them in the trailer as backups.

Dave

 

[DAVECS1]

The halfshafts are actually a bit smaller, but they look to be of better material. The CVs are a little different. They are a smidge bigger, and there is more machining. They also seem to be of a different material.



Bottom shaft is stock gt

 

[ihavefat]

Just out of curiosity , those of you with broken shafts, did you guys happen to have any of the nannies on? Advancetrac/stability

 

[ddozier]

Just out of curiosity , those of you with broken shafts, did you guys happen to have any of the nannies on? Advancetrac/stability

I always run with Advancetrac disabled.

Dave

 

[higdominator]

Curious if there have been any 350 shaft failures? I would assume they designed them so that the joints were more robust due to this very reason.

That being said, I was going to sell my DSS out of the car since I don't do any drag events any more, but I will likely now leave them in since I plan to track this car a considerable amount.

Thanks for the heads up.

 

[Brent Dalton]

Getting caught up on surfing through the forums. Glad to hear it didn't wreck your weekend Dave. Since the GT350 ones are $320, I may go ahead and pick a set up.

 

[Grim12]

Curious if there have been any 350 shaft failures? I would assume they designed them so that the joints were more robust due to this very reason.

That being said, I was going to sell my DSS out of the car since I don't do any drag events any more, but I will likely now leave them in since I plan to track this car a considerable amount.

Thanks for the heads up.

Curious about the same thing. Was looking to upgrade to the 350 halfshafts because of the reasonable price and no real weight penalty over the GT halfshafts. Staying NA so I'm hoping they will work.

 

[ddozier]

I put in the GT350 shafts today, and I believe they will do the job well without the need to go beyond them to solve the problem of the failing shafts on track. The GT350 shafts are made slightly different, the outer joint is almost .5" longer than the GT shafts. It also seems that the return spring in the inboard joint is stronger than the GT shafts.

I believe based on the failure of my GT shaft that the extra .5" of length will keep the inner joint from extending out of its cup enough to prevent the joint from catching the retainer ring. This should be enough to keep it from failing, or at least I hope so.

As a side note, I have purchased 3 shafts in total from Ford, 1 GT shaft and both GT350 shafts, all three were packaged poorly and all three had damage to the dust shields that protect the outer bearing. I was able to straighten them but be aware if you order shafts inspect them on delivery.

Dave

 

[DAVECS1]

Mine were also packaged poorly with a bent dust shield. When you run your car next time Dave, I will be curious to see if you notice any new noises. When I have everything off and Let the engine brake the car on a smooth road I get a hint of drivetrain noise in the back after the axle install. I dont notice it during normal driving.

 

[wildcatgoal]

Ford can't package heavy objects for the life of them. I got a track pack that looked like it went through a war on its way to me. Sent it right back.

This is scary to see. I plan to track my car about 5 times this year if finances work out. Arg.

Guess I'll cross my fingers.

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